JPH08165396A - Thermochromic resin composition - Google Patents

Abstract

PURPOSE: To provide thermochromic resin compsn. which, in a low temp. region, can simply conduct display according to the ambient temp. by bonding, coating and printing onto a working surface, has light modulating capability according to temp. change even in sole use, is inexpensive and practical, and has heat resistance. CONSTITUTION: This resin compsn. comprises a mixture of a low-viscosity vinylidene fluoride/hexafluoropropylene copolymer, a butyl (meth)acrylate polymer and a phthalic ester compd. and has a haze of 50 deg.C or below. Alternatively, the resin compsn. comprises a crosslinking product of the above mixture having a haze of 50 deg.C or below.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an LCST type (Lower Cr
itical Solution Temperature: Lower critical solution temperature type)
The present invention relates to a resin composition having the characteristic that the transparency changes, that is, the light transmittance changes at a transition temperature (hereinafter referred to as “cloud point”) as a boundary. The present invention relates to a thermochromic resin composition in which dots are expressed.

[0002]

2. Description of the Related Art In recent years, thermochromic resin compositions utilizing the compatibility-phase separation phenomenon of polymer blends have been proposed. In this polymer blend system, the blended polymers are uniformly mixed and transparent at the molecular level in the compatible state, but in the phase separated state, light is scattered and becomes cloudy because a micro phase separated structure is formed. The polymer blend system having an LCST type phase diagram has a characteristic that one phase is transparent on the low temperature side, but it is opaque by separating into two phases on the high temperature side from the cloud point.

Conventionally, a polymer blend system in which a vinylidene fluoride polymer and a (meth) acrylic acid ester polymer are combined has an LCST type phase diagram,
Various systems are known that cause reversible phase-separation.
For example, JP-A-61-190546 and JP-A-6-190546.
Japanese Unexamined Patent Publication No. 2-188037 discloses a polymer using a vinylidene fluoride-hexafluoroacetone copolymer as a vinylidene fluoride polymer.
JP-A-36092 and JP-A-3-42278 disclose the use of vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer as a vinylidene fluoride-based polymer.

First, in JP-A-61-190546, a combination of vinylidene fluoride-hexafluoroacetone copolymer and methyl acrylate or ethyl acrylate may have cloud points of 190 ° C. and 170 ° C., respectively. It is shown. Also, JP-A-62-1880
No. 37, 235 discloses a combination with a methyl methacrylate polymer or an ethyl methacrylate polymer.
It has been shown to have a cloud point of 2400C.

Further, in JP-A-3-36092 and JP-A-3-42278, a combination of vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer and methyl methacrylate gives 1
It is shown to have a cloud point of 47 ° C, 125 ° C.

In Japanese Patent Publication No. 63-65706, vinylidene fluoride copolymer, vinylidene fluoride-
Trifluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoroisobutene copolymer, vinylidene fluoride-
It is said that the compatibility-phase separation phenomenon is exhibited also in polymers such as chlorotrifluoroethylene copolymer, vinylidene fluoride-vinyl fluoride copolymer, vinylidene fluoride-hexafluoropropylene copolymer and the like.

[0007]

However, when the above polymer blend system is applied as a thermochromic resin composition, there are the following problems. First, vinylidene fluoride-based polymer using hexafluoroacetone as a raw material is a special polymer, and it is difficult to obtain it as an industrial product. Difficult,
It is inevitably very expensive and not suitable for practical use. Also,
Hexafluoroacetone is a toxic substance and must be handled with extreme caution. Further, from the viewpoint of obtaining a compatibilization-phase separation phenomenon in a wider temperature range, particularly in a low temperature range where energy is smaller in terms of energy,
The development of the cloud point at a much lower temperature range than the combination of the vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer and the methyl methacrylate polymer described above (cloud point of 147 ° C. and 125 ° C.). desired. Further, since the conventional polymer blend system is thermoplastic, when heated to develop the compatibility-phase separation phenomenon, deformation and flow are naturally observed and sufficient heat resistance is not maintained.

The present invention has been made to solve the above problems, and the purpose thereof is 50
In a low temperature range of ℃ or below, you can easily display according to the ambient temperature by adhering, coating, printing, etc. on the use surface. Even when used alone, it has a dimming function that responds to temperature changes. Another object of the present invention is to provide a thermochromic resin composition which is practical and practical and has excellent heat resistance.

[0009]

In order to achieve the above object, the thermochromic resin composition according to the present invention comprises a low viscosity vinylidene fluoride-hexafluoropropylene copolymer, a butyl (meth) acrylate polymer and phthalic acid. It is characterized by comprising a mixture with an ester compound and having a cloud point of 50 ° C. or lower.

The low-viscosity vinylidene fluoride-hexafluoropropylene copolymer means a polymer which is semi-liquid at room temperature, and the viscosity of a polymer which is solid at room temperature is defined by Mooney viscosity. The concept of liquid viscosity is directly applied to the low-viscosity vinylidene fluoride-hexafluoropropylene copolymer. That is, it includes all those whose viscosity can be defined in units of ps (poise). Specifically, the low-viscosity vinylidene fluoride-hexafluoropropylene copolymer according to the present invention has a viscosity of 50 to 50.
The viscosity at 100 ° C. is in the range of 5000 to 1 ps, preferably 1000 to 10 ps. As an example of such a copolymer, the viscosity at 100 ° C. is 2000 cps, and the viscosity at 60 ° C. is 500 ps. Those are available as industrial products.

As the butyl (meth) acrylate polymer, a polymer of n-butyl (meth) acrylate is preferably used.

Examples of the phthalate compound include dimethyl phthalate, diethyl phthalate, methyl ethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, diisooctyl phthalate, dihexadecyl phthalate, dicyclohexyl phthalate, Examples thereof include diphenyl phthalate, dibenzyl phthalate, didecyl phthalate, diisodecyl phthalate, didodecyl phthalate, dinonyl phthalate, dilauryl phthalate, decylisooctyl phthalate, butylbenzyl phthalate, and butyllauryl phthalate. Not limited.

In the present invention, the above-mentioned low-viscosity vinylidene fluoride-hexafluoropropylene copolymer, butyl (meth) acrylate polymer and phthalate compound are mixed to obtain a desired resin composition. The mixing ratio at that time can be any ratio within the range that does not affect the compatibility-phase separation phenomenon.

The mixing method is also not particularly limited. For example, a method of dissolving the above three components in an organic solvent such as methyl ethyl ketone and mixing them, and then removing the organic solvent, or a low-viscosity fluorinated monomer of butyl (meth) acrylate is used. A method in which a vinylidene-hexafluoropropylene copolymer and a phthalate compound are dissolved and then a monomer of butyl (meth) acrylate is polymerized may be considered.

Next, a thermochromic resin composition according to another aspect of the present invention is a mixture of a low-viscosity vinylidene fluoride-hexafluoropropylene copolymer, a butyl (meth) acrylate polymer and a phthalate ester compound. And a cloud point of 50 ° C. or lower.

The method of crosslinking a mixture of a low-viscosity vinylidene fluoride-hexafluoropropylene copolymer, a butyl (meth) acrylate polymer and a phthalate compound is carried out by chemical crosslinking by adding a crosslinking agent, Radiation crosslinking by irradiation Either crosslinking method may be used.

Preferred examples of the cross-linking agent used when chemical cross-linking is adopted include polyfunctional (meth) acrylic acid esters. Examples of the polyfunctional (meth) acrylic acid ester include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1,3- Butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate,
1,6-hexanediol di (meth) acrylate,
E of 1,10-decanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin di (meth) acrylate, bisphenol A
O adduct di (meth) acrylate, tetrabromobisphenol A EO adduct di (meth) acrylate, neopentyl glycol di (meth) acrylate, dibromo neopentyl glycol di (meth) acrylate, 2-
Hydroxy 1,3-di (meth) acryloxypropane,
2,2-bis [4-((meth) acryloxyethoxy)
Phenyl] propane, 2,2-bis [4-((meth) acryloxydiethoxy) phenyl] propane, 2,2-
Bis [4-((meth) acryloxypolyethoxy) phenyl] propane, polyethylene glycol # 200 di (meth) acrylate, polyethylene glycol # 40
0 (meth) diacrylate, polyethylene glycol #
600 di (meth) acrylate, polyethylene glycol # 1000 di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. are considered. Any polyfunctional (meth) acrylic acid ester that acts as a crosslinking agent may be used.

The amount of the polyfunctional (meth) acrylic acid ester added is not particularly limited as long as it does not affect the compatibility-phase separation phenomenon, but is preferably low-viscosity vinylidene fluoride-hexafluoropropylene. The amount is 0.05 parts by weight or more based on 100 parts by weight of the mixture of the copolymer, the butyl (meth) acrylate polymer, and the phthalate ester compound. If the amount added is less than 0.05 parts by weight, deformation and flow due to heating are not suppressed, and the effect of improving heat resistance due to crosslinking cannot be exhibited. The addition amount is appropriately selected so as to obtain a desired degree of crosslinking depending on the application.

When radiation cross-linking is adopted, either electron beam cross-linking or gamma ray cross-linking may be used, but electron beam cross-linking is easier in radiation control.

Incidentally, a thermochromic resin composition of a polymer blend system of a vinylidene fluoride polymer and a (meth) acrylic acid ester polymer showing a conventional LCST type phase diagram is generally compatible when crosslinked. Although the phase separation phenomenon is not clearly manifested, in the present invention, surprisingly, the compatibility-phase separation phenomenon is reversibly manifested in a low temperature region of 50 ° C. or lower.

[0021]

The function of the thermochromic resin composition of the present invention is LC
Shows the ST type phase diagram and the transparency changes at the cloud point.
That is, it has a characteristic that the light transmittance changes. By utilizing this characteristic, a display function and a dimming function function according to a temperature change are possible.

By gradually cooling the cloudy resin composition to a temperature lower than the cloud point and higher than the glass transition point of the resin composition, the resin composition changes from the cloudy state to the transparent state. Due to this characteristic, it is possible to reversibly perform the above-mentioned display action and light control function action with the cloud point as a boundary. It is also possible to maintain the cloudy state by rapidly cooling the cloudy resin composition to a temperature below the glass transition point. The cloud point can be arbitrarily set by selecting the mixing ratio of the low-viscosity vinylidene fluoride-hexafluoropropylene copolymer, the butyl (meth) acrylate polymer, and the phthalate compound.

Further, when the thermochromic resin composition of the present invention is provided with a three-dimensional network structure by irradiation with a crosslinking agent or radiation, deformation and flow due to heating are suppressed and heat resistance is improved. Therefore, it is suitable for use in applications where heat resistance is particularly required. Despite having a three-dimensional network structure, this thermochromic resin composition causes a cloudiness change on the higher temperature side beyond the cloud point and has a sufficient function as a display or a light control material. Furthermore, if the thermochromic resin composition crosslinked by the above means in the cloudy state is placed on the lower temperature side than the cloud point and on the higher temperature side than the glass transition point of the resin composition, the resin composition rapidly changes from the cloudy state to the transparent state. Changes to. With such characteristics, it is possible to reversibly perform the above-mentioned display action and light control function action at the cloud point. It is also possible to maintain the cloudy state by rapidly cooling the thermochromic resin composition that has been crosslinked by the above means in the cloudy state to a temperature below the glass transition point. The cloud point can be arbitrarily set by selecting the mixing ratio of the low-viscosity vinylidene fluoride-hexafluoropropylene copolymer, the butyl (meth) acrylate polymer, and the phthalate compound.

The thermochromic resin composition of the present invention comprises
The application is not limited as long as the conversion from the transparent state to the cloudy state can be used without being limited to the display function and the light control function described above. For example, when it is used for a recording medium, it is extremely advantageous because it can realize the conversion of the transparent-opaque state at low temperature, that is, low energy. There are no particular restrictions on the method for raising the temperature of the thermochromic resin composition to above the cloud point, and various types of heaters, warm air, etc. that are commonly used, as well as laser light, electromagnetic waves, etc. may be used.

[0025]

The following examples serve to explain the present invention more specifically. The invention is not limited by these examples.

Example 1 In this Example, a low-viscosity vinylidene fluoride-hexafluoropropylene copolymer having a viscosity of 2000 cps at 100 ° C. and a semi-liquid state at room temperature was used, and a butyl (meth) acrylate polymer was used as acrylic acid. n-Butyl was used as the phthalate compound, and butylbenzyl phthalate was used.

30 g of low-viscosity vinylidene fluoride-hexafluoropropylene copolymer and butylbenzyl phthalate 3
0 g was dissolved in 70 g of n-butyl acrylate monomer, and 2 g of benzoin methyl ether as a photopolymerization initiator was further dissolved to obtain a uniform monomer solution.
Next, this monomer solution was irradiated with ultraviolet rays for 60 minutes using a 40 W black light to perform photopolymerization. The obtained polymer composition was colorless and transparent at an environmental temperature of 20 ° C., and when heated, it became cloudy at 38 ° C. and a cloud point was developed. Also,
It was confirmed that when gradually cooled to 20 ° C., it returned to colorless and transparent.

Example 2 In this example, a low-viscosity vinylidene fluoride-hexafluoropropylene copolymer having a viscosity of 2000 cps at 100 ° C. and a semi-liquid state at room temperature, and a butyl (meth) acrylate polymer as acrylic acid were used. Dioctyl phthalate was used as n-butyl as the phthalate compound.

30 g of low-viscosity vinylidene fluoride-hexafluoropropylene copolymer and 10 g of dioctyl phthalate
Was dissolved in 70 g of n-butyl acrylate monomer, and 2 g of benzoin methyl ether as a photopolymerization initiator was further dissolved to obtain a uniform monomer solution. Next, this monomer solution was irradiated with ultraviolet rays for 60 minutes using a 40 W black light to perform photopolymerization. The obtained polymer composition is colorless and transparent at an environmental temperature of 20 ° C.,
When heated, it became cloudy at 50 ° C. and a cloud point was developed. Also, 20
It was confirmed that when it was gradually cooled to ℃, it returned to colorless and transparent again.

Example 3 This example shows an example in which a mixture of a low-viscosity vinylidene fluoride-hexafluoropropylene copolymer, a butyl (meth) acrylate polymer and a phthalate compound was crosslinked with a crosslinking agent. A polyfunctional (meth) acrylic acid ester was used as the crosslinking agent. Tripropylene glycol diacrylate was used as the polyfunctional (meth) acrylic acid ester.

A monomer solution similar to that used in Example 2 was prepared, and tripropylene glycol diacrylate 1 was added thereto.
After adding g, photopolymerization was performed under the same conditions as in Example 2. The obtained polymer composition was colorless and transparent at an environmental temperature of 20 ° C., and when heated, it became cloudy at 39 ° C. and a cloud point was developed. Moreover, it was confirmed that when it was gradually cooled to 20 ° C., it returned to colorless and transparent. At this time, no deformation or flow due to heating was observed. Furthermore, when this composition was placed in methyl ethyl ketone and allowed to stand for 24 hours, gel was confirmed and it was confirmed that it was crosslinked.

Example 4 This example also shows an example in which a mixture of a low-viscosity vinylidene fluoride-hexafluoropropylene copolymer, a butyl (meth) acrylate polymer and a phthalate ester compound was crosslinked with a crosslinking agent. Therefore, tripropylene glycol diacrylate was used as the polyfunctional (meth) acrylic acid ester as the crosslinking agent.

A monomer solution similar to that in Example 1 was prepared,
After adding 1 g of tripropylene glycol diacrylate to this, photopolymerization was performed under the same conditions as in Example 1.
The obtained polymer composition was colorless and transparent at an ambient temperature of 20 ° C., and when heated, it became cloudy at 35 ° C. and a cloud point was developed.
Moreover, it was confirmed that when it was gradually cooled to 20 ° C., it returned to colorless and transparent. At this time, no deformation or flow due to heating was observed. Furthermore, when this composition was placed in methyl ethyl ketone and allowed to stand for 24 hours, gel was confirmed and it was confirmed that it was crosslinked.

[0034]

As described above, according to the present invention, it is possible to easily perform the display according to the ambient temperature by adhering, coating, printing or the like on the surface to be used, and the temperature change even when used alone. It is possible to provide an inexpensive and practical thermochromic resin composition having a light control function according to the above and capable of exhibiting a cloud point in a low temperature range of 50 ° C. or lower.
Further, the thermochromic resin composition obtained by crosslinking with a crosslinking agent can be provided with excellent heat resistance.

Claims (2)

[Claims] 1. A mixture of a low-viscosity vinylidene fluoride-hexafluoropropylene copolymer, a butyl (meth) acrylate polymer and a phthalate ester compound,
A thermochromic resin composition having a cloud point of ℃ or less. 2. A crosslinked product of a mixture of a low-viscosity vinylidene fluoride-hexafluoropropylene copolymer, a butyl (meth) acrylate polymer and a phthalate ester compound, and having a cloud point of 50 ° C. or lower. A characteristic thermochromic resin composition.